Vertical profile optimisation of a self-aligned SiGeC HBT process with an n-cap emitter

SiGeC heterojunction bipolar transistors (HBTs) with a cut-off frequency of f/sub T/>150GHz, have been realised with an n-type emitter cap, using a self-aligned integration scheme. Device simulations were used to tune the emitter base side of the non-selective epitaxially grown SiGeC layer. The experimental results are in very good agreement with the predictions.